The pyrovalve is currently the only zero-leak valve qualified for spaceflight in the U.S. aerospace industry. The pyrovalve design can have reliability issues. Normally-Open (NO) and Normally-Closed (NC) pyrovalves use a primary charge and two redundant pyrotechnic initiators to permanently open and close the valve, respectively. The explosive reaction occurs in close proximity to propellant. Therefore, any internal leakage of the product gases into the wetted volume, known as blow by, could cause a decomposition of the propellant and catastrophic failure of the spacecraft. Thus, the reliability of the valve is crucial.
Pyrovalves are one-time-use. Therefore, individual units cannot be tested for functionality. There is very limited functional testing in situ on the vehicle. Power cannot be supplied to the valve while the initiators are installed. Verification of initiator installation is therefore impossible, creating a potential for loose, damaged, or cross-connected pins that could result in the failure of the pyrovalve and potential loss of the spacecraft. Designers of propulsion systems typically use multiple pyrovalves to mitigate these risks, which increases the mass and cost of the system. Once the initiators are installed, careful handling of the spacecraft must be taken to prevent premature actuation.
In addition, there are limited sources for purchasing pyrovalves.
A need exists for a valve that provides a zero-leak seal using a safer, more reliable actuator with a verifiable function.